1. Field of the Invention
The present invention relates generally to switching systems, and specifically to a technique for monitoring the quality of an ATM (asynchronous transfer mode) switching system at periodic intervals for diagnostic purposes.
2. Description of the Related Art
In order to monitor the internal quality of an ATM self-routing switch, or a digital cross-connect system that transports STM-N (synchronous transport modules level N) signals, one approach would involve detecting an idle cell at each inlet of the switch, writing a supervisory bit sequence into the idle cell and detecting the supervisory bit sequence from each outlet of the switch to determine the quality of the path through which the idle cell has propagated. Another approach would involve the use of a buffer for storing AIM cells. A supervisory cell containing a supervisory bit sequence is generated and multiplexed with the ATM cells from the buffer. However, either of the approaches tends to lower the throughput of the switching system.